package com.example.nio;

import org.springframework.util.StringUtils;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.util.Iterator;

/**
 * TODO: 这里要写注释的!
 */
public class TimeClientHandle implements Runnable {
    private String host;
    private int port;
    private Selector selector;
    private SocketChannel socketChannel;
    private volatile boolean stop;

    public TimeClientHandle(String host,int port){
        this.host= StringUtils.isEmpty(host)?"127.0.0.1":host;
        this.port= port;
        try {
            selector= Selector.open();
            socketChannel= SocketChannel.open();
            socketChannel.configureBlocking(false);
        } catch (IOException e) {
            e.printStackTrace();
            System.exit(1);
        }
    }

    @Override public void run() {
        try{
            doConnect();
        }catch (Exception e){
            e.printStackTrace();
            System.exit(1);
        }
        while (!stop){
            try {
                selector.select(1000);
                Iterator<SelectionKey> it= selector.selectedKeys().iterator();
                SelectionKey key;
                while (it.hasNext()){
                    key= it.next();
                    it.remove();
                    try{
                        handleInput(key);
                    }catch (Exception e){
                        if(key!=null){
                            key.cancel();
                            if(key.channel()!=null){
                                key.channel().close();
                            }
                        }
                        e.printStackTrace();
                    }
                }
            } catch (IOException e) {
                System.exit(1);
            }
        }
        if(selector!=null){
            try {
                selector.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    private void handleInput(SelectionKey key) throws IOException {
        if(key.isValid()){
            SocketChannel sc= (SocketChannel) key.channel();
            if(key.isConnectable()){
                if(sc.finishConnect()){
                    sc.register(selector,SelectionKey.OP_READ);
                    doWrite(sc);
                }else {
                    System.exit(1);
                }
            }
            if(key.isReadable()){
                ByteBuffer byteBuffer= ByteBuffer.allocate(1024);
                int readBytes= sc.read(byteBuffer);
                if(readBytes>0){
                    byteBuffer.flip();
                    byte[] bytes= new byte[byteBuffer.remaining()];
                    byteBuffer.get(bytes);
                    String body= new String(bytes,"utf-8");
                    System.out.println("now is: "+body);
                    //this.stop= true;
                }else if(readBytes<0){
                    key.cancel();
                    sc.close();
                }
            }
        }
    }

    private void doConnect() throws IOException {
        if(socketChannel.connect(new InetSocketAddress(host, port))){
            socketChannel.register(selector,SelectionKey.OP_READ);
            doWrite(socketChannel);
        }else {
            socketChannel.register(selector,SelectionKey.OP_CONNECT);
        }
    }

    private void doWrite(SocketChannel channel) throws IOException {
        byte[] bytes= "query time order".getBytes();
        ByteBuffer byteBuffer= ByteBuffer.allocate(bytes.length);
        byteBuffer.put(bytes);
        byteBuffer.flip();
        channel.write(byteBuffer);
        if(!byteBuffer.hasRemaining()){//判断缓冲区数据是否发送完毕
            System.out.println("send order 2 server succeed.");
        }
    }
}
